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But coal is still 49%. The whole point of nuclear in a carbon-free, mostly-renewable grid is to avoid needing enormous amounts of storage and overproduction. Th

by DennisP 1mo ago

But coal is still 49%. The whole point of nuclear in a carbon-free, mostly-renewable grid is to avoid needing enormous amounts of storage and overproduction. That's a need that doesn't come up when you're still half fossil. If you want to decarbonize as fast as possible, it makes sense to focus on rolling out wind/solar/battery as fast as possible for now, but keep developing nuclear technology to cover the last bit where it starts getting especially expensive to replace fossil with renewables without losing reliable power. That's exactly what China appears to be doing. They're not just building a few reactors, they're also the world leaders in developing various GenIV designs, like molten salt reactors.

ViewTrick1002 1mo ago
The problem is that the economics of a ”firming”/”peaking” nuclear reactor is absolutely stupid due to essentially being only fixed costs. It is already stupidly expensive when running at 100% 24/7. Now try running it only when renewables and storage doesn’t deliver.
- Animats 1mo ago
  That's a fundamental problem with nuclear plants. Their classic "baseload" niche is gone. Like the intermittent sources, wind and solar, they need storage to hold what they overproduce during peak periods. This is also true of geothermal, which, like nuclear, is almost all fixed capital cost.
  - sfn42 1mo ago
    It's only a problem because of capitalism. Every plant needs to independently make money, so nobody wants to be the ones spinning down because that's their profit margin dwindling. But society would be better off with excess generation. So we either need a system where some are incentivized to spin down, perhaps by being paid a consistent amount regardless or something like that, or we need publicly owned power generation that doesn't care about profit.
    - ViewTrick1002 1mo ago
      This argument assumes we must build nuclear power. The problem is that electricity is fundamentally priced on the margin. Now that we are moving beyond a purely centralized design. Think about a homeowner or factory with their own renewables and storage. They fundamentally operate on marginal price by choosing when they use their own system and when they buy from the grid. If you add state owned reliable power to this mix they will cherry-pick. Their own cheap electricity when it delivers and the states subsidized reliable electricity when it doesn’t. We can try add all manner of markets, fixed connection costs and what not to this but all it does is introduce strange arbitrage possibilities in the market. Which is why we have settled on net energy markets and then the lowest possible amount of ancillary markets to shore up any gaps which would cause problems for the larger society.
      - sfn42 1mo ago
        We have needed to build nuclear power since the day it was invented. The amount of fossil fueled power generation is indisputable proof of that. The only way we don't need nuclear power is if we have some other way of producing the energy we need without dooming the planet, and obviously we do not as we're still burning billions of tons of coal every year. Not to mention gas. We could have made power generation fully fossil free many decades ago if we actually took climate change seriously. It would have been fine. Sure fossil fuels may have been cheaper, but if you include the damage they're already causing and will cause in the future you could multiply the cost of nuclear by orders of magnitude and it would still come out on top. Plus higher investment would lead to faster improvement in the technology, mass production of components and lower cost etc.
        ViewTrick1002 1mo ago
        Thats crying over spilled milk. We’ve spent the past 70 years trying to build out nuclear power. It didn’t deliver cheap energy. Today, renewables and storage are the cheapest energy sources in human history. They are filling the gap nuclear power never managed to fill.
bryanlarsen 1mo ago
The most cost efficient new-build grid is 90-98% solar/wind/battery depending on your locales insolation & wind coverage. (Source Ember Energy) The remaining 2-10% is nat gas, if you have a piped source, or coal if you don't. But 98% renewable doesn't mean you can hit 100% by adding 2% more of something else, it means your something else has to supply ~100% of the power 2% of the time. If China is aiming for that cost-optimal 90-98% renewables, that means they need to build a lot of coal.
- fpoling 1mo ago
  And they build a lot of modern coal power station with over 45% efficiency and flexibility in power output.
- idiotsecant 1mo ago
  Solar battery is not by any stretch of any possible definition the cheapest generation to deploy. Not even close. We do a disservice to the entire conversation saying easily falsifiable things like that. At 90% penetration solar + battery has a LFSCOE somewhere around $800/mwh depending on the study. Natural gas is something like 30-60. Solar panels are cheap. Building the required transmission and storage to service those panels is far more expensive than the panels themselves. Increased renewable generation is an important goal, but we need to let the facts guide the path, not the other way around.
  - ViewTrick1002 1mo ago
    Please, don’t cite the LFSCOE paper again. Citing it shows you have a beef against renewables. That paper uses one renewable source, like only solar, and 2018-19 cost data for storage. A real grid is made up of a mix of sources, which is why the research lately has focused on system costs. All those analyses find that renewable grids are far cheaper than if involving new built nuclear power. Here are two modern papers on the subject: https://www.csiro.au/-/media/Energy/GenCost-2025-26-Final/GenCost_2025-26_Final_Report_20260715.pdf https://www.csiro.au/-/media/Energy/GenCost-2025-26-Final/Ge... https://www.sciencedirect.com/science/article/pii/S0360544226009837 https://www.sciencedirect.com/science/article/pii/S036054422...
boplicity 1mo ago
The coal argument about China doesn't hold water when you look at what they're actually building. Around 80% of their new power sources are renewable, and 10 to 15% is coal. They're aggressively focusing primarily on building renewable -- so to say that their coal is 49% is either misleading or entirely missing the point.
- DennisP 1mo ago
  That's why I said in my comment that China is "rolling out wind/solar/battery as fast as possible."
- p2detar 1mo ago
  This assumes that the renewables built are actually contributing to the economy, which we don‘t actually know for sure. In fact there was an article stating that they discard a lot of the energy produced because the grid cannot deliver. [1] > China, the world's top producer of solar power, rejected 360 terawatt-hours (TWh) of clean power from January to June, up 49% from the same period a year earlier, according to a report this month by Global Energy Monitor (GEM) and the Center for Research on Energy and Clean Air (CREA). 1 - https://www.reuters.com/business/energy/china-leads-wave-clean-power-wastage-grids-globally-hit-limits-2026-08-17/ https://www.reuters.com/business/energy/china-leads-wave-cle...
marshray 1mo ago
Enormous amounts of storage is awesome and overproduction is a good thing when its marginal cost is ~zero.

by DennisP 1mo ago

ViewTrick1002 1mo ago

The problem is that the economics of a ”firming”/”peaking” nuclear reactor is absolutely stupid due to essentially being only fixed costs. It is already stupidly expensive when running at 100% 24/7. Now try running it only when renewables and storage doesn’t deliver.

Animats 1mo ago
That's a fundamental problem with nuclear plants. Their classic "baseload" niche is gone. Like the intermittent sources, wind and solar, they need storage to hold what they overproduce during peak periods. This is also true of geothermal, which, like nuclear, is almost all fixed capital cost.
- sfn42 1mo ago
  It's only a problem because of capitalism. Every plant needs to independently make money, so nobody wants to be the ones spinning down because that's their profit margin dwindling. But society would be better off with excess generation. So we either need a system where some are incentivized to spin down, perhaps by being paid a consistent amount regardless or something like that, or we need publicly owned power generation that doesn't care about profit.
  - ViewTrick1002 1mo ago
    This argument assumes we must build nuclear power. The problem is that electricity is fundamentally priced on the margin. Now that we are moving beyond a purely centralized design. Think about a homeowner or factory with their own renewables and storage. They fundamentally operate on marginal price by choosing when they use their own system and when they buy from the grid. If you add state owned reliable power to this mix they will cherry-pick. Their own cheap electricity when it delivers and the states subsidized reliable electricity when it doesn’t. We can try add all manner of markets, fixed connection costs and what not to this but all it does is introduce strange arbitrage possibilities in the market. Which is why we have settled on net energy markets and then the lowest possible amount of ancillary markets to shore up any gaps which would cause problems for the larger society.
    - sfn42 1mo ago
      We have needed to build nuclear power since the day it was invented. The amount of fossil fueled power generation is indisputable proof of that. The only way we don't need nuclear power is if we have some other way of producing the energy we need without dooming the planet, and obviously we do not as we're still burning billions of tons of coal every year. Not to mention gas. We could have made power generation fully fossil free many decades ago if we actually took climate change seriously. It would have been fine. Sure fossil fuels may have been cheaper, but if you include the damage they're already causing and will cause in the future you could multiply the cost of nuclear by orders of magnitude and it would still come out on top. Plus higher investment would lead to faster improvement in the technology, mass production of components and lower cost etc.
      - ViewTrick1002 1mo ago
        Thats crying over spilled milk. We’ve spent the past 70 years trying to build out nuclear power. It didn’t deliver cheap energy. Today, renewables and storage are the cheapest energy sources in human history. They are filling the gap nuclear power never managed to fill.

bryanlarsen 1mo ago

The most cost efficient new-build grid is 90-98% solar/wind/battery depending on your locales insolation & wind coverage. (Source Ember Energy) The remaining 2-10% is nat gas, if you have a piped source, or coal if you don't. But 98% renewable doesn't mean you can hit 100% by adding 2% more of something else, it means your something else has to supply ~100% of the power 2% of the time. If China is aiming for that cost-optimal 90-98% renewables, that means they need to build a lot of coal.

fpoling 1mo ago
And they build a lot of modern coal power station with over 45% efficiency and flexibility in power output.
idiotsecant 1mo ago
Solar battery is not by any stretch of any possible definition the cheapest generation to deploy. Not even close. We do a disservice to the entire conversation saying easily falsifiable things like that. At 90% penetration solar + battery has a LFSCOE somewhere around $800/mwh depending on the study. Natural gas is something like 30-60. Solar panels are cheap. Building the required transmission and storage to service those panels is far more expensive than the panels themselves. Increased renewable generation is an important goal, but we need to let the facts guide the path, not the other way around.
- ViewTrick1002 1mo ago
  Please, don’t cite the LFSCOE paper again. Citing it shows you have a beef against renewables. That paper uses one renewable source, like only solar, and 2018-19 cost data for storage. A real grid is made up of a mix of sources, which is why the research lately has focused on system costs. All those analyses find that renewable grids are far cheaper than if involving new built nuclear power. Here are two modern papers on the subject: https://www.csiro.au/-/media/Energy/GenCost-2025-26-Final/GenCost_2025-26_Final_Report_20260715.pdf https://www.csiro.au/-/media/Energy/GenCost-2025-26-Final/Ge... https://www.sciencedirect.com/science/article/pii/S0360544226009837 https://www.sciencedirect.com/science/article/pii/S036054422...

boplicity 1mo ago

The coal argument about China doesn't hold water when you look at what they're actually building. Around 80% of their new power sources are renewable, and 10 to 15% is coal. They're aggressively focusing primarily on building renewable -- so to say that their coal is 49% is either misleading or entirely missing the point.

DennisP 1mo ago
That's why I said in my comment that China is "rolling out wind/solar/battery as fast as possible."
p2detar 1mo ago
This assumes that the renewables built are actually contributing to the economy, which we don‘t actually know for sure. In fact there was an article stating that they discard a lot of the energy produced because the grid cannot deliver. [1] > China, the world's top producer of solar power, rejected 360 terawatt-hours (TWh) of clean power from January to June, up 49% from the same period a year earlier, according to a report this month by Global Energy Monitor (GEM) and the Center for Research on Energy and Clean Air (CREA). 1 - https://www.reuters.com/business/energy/china-leads-wave-clean-power-wastage-grids-globally-hit-limits-2026-08-17/ https://www.reuters.com/business/energy/china-leads-wave-cle...

marshray 1mo ago

Enormous amounts of storage is awesome and overproduction is a good thing when its marginal cost is ~zero.